Husheng Li Sharon M. Betz H. Vincent Poor Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels. 1981-1993 2007 55 IEEE Transactions on Signal Processing 5-2 http://doi.ieeecomputersociety.org/10.1109/TSP.2007.893229 db/journals/tsp/tsp55.html#LiBP07